In Escherichia coli YfhQ is the only methyltransferase responsible for the formation of 2'-O-methylcytidine32 in tRNA. No methylation of cytosine34 in tRNALeu(CAA). In vitro the enzyme 2-O-methylates cytidine32 of tRNASer1 and uridine32 of tRNAGln2.